<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表格合并</title>
</head>
<body>
    <table border="1px" cellspacing="0" cellpadding="0" width="600px">
        <tr>
            <td colspan="3">已登录信息如下：</td>
        </tr>
        <tr>
            <td>张三</td>
            <td>男</td>
            <td>18岁</td>
        </tr>
        <tr>
            <td>李四</td>
            <td>女</td>
            <td>20岁</td>
        </tr>
    </table>
</body>
</html>